Helmet



FIG. 1 is a top, front perspective view of a helmet showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top view thereof.

The interior of the helmet (visible through the openings in the helmet) forms no part of the claimed design. 

CLAIM The ornamental design for a helmet, as shown and described. 